service-aware networks over shared wireless access infrastructure

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Service-Aware Networks over Shared Wireless Access Infrastructure Luiz A. DaSilva Professor of Telecommunications, Trinity College Dublin Professor, Virginia Tech II International Workshop on Challenges and Trends on Broadband Wireless Mobile Access Networks – Beyond LTE-A Campinas, Brasil, 5 November 2014

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II International Workshop on Challenges and Trends on Broadband Wireless Mobile Access Networks – Beyond LTE-A

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Page 1: Service-aware Networks over Shared Wireless Access Infrastructure

Service-Aware Networks over Shared Wireless Access Infrastructure

Luiz A. DaSilva!Professor of Telecommunications, Trinity College Dublin

Professor, Virginia Tech

II International Workshop on Challenges and Trends on Broadband Wireless Mobile Access Networks – Beyond LTE-A!

Campinas, Brasil, 5 November 2014

Page 2: Service-aware Networks over Shared Wireless Access Infrastructure

Sharing, Sharing, Sharing

• Infrastructure sharing among operators !

• Spectrum sharing (LSA, 3-tier, …) !

• Sharing of crowdsourced access !To improve coverage/capacity, to improve energy efficiency (or both)

Page 3: Service-aware Networks over Shared Wireless Access Infrastructure

Our vision: a future based on sharing and virtualisation of wireless networks

Page 4: Service-aware Networks over Shared Wireless Access Infrastructure

Increased efficiency and lower costs through:

1. Incentives for the deployment of localised (small cell, primarily) infrastructure by medium-sized and small operators.

2. The ability to provide service over infra‐structure that employs heterogeneous technologies, and has different properties and ownership.

3. Improved service in currently under‐served areas.

4. The ability to offer virtual wireless networks with different associated quality of experience, at different price points.

Page 5: Service-aware Networks over Shared Wireless Access Infrastructure

Network planning!

siloed, individual networks

limited consideration for complementary technologies (eg., WiFi hotspots)

quality of service through overprovisioning

Network planning!

private plus shared assets

other technologies are an integral part

service requirements (not coverage + capacity for all) are the main driver

Page 6: Service-aware Networks over Shared Wireless Access Infrastructure

Network planning and expansion

driven by over-the-top service needs

considering sharing

Significant CAPEX and energy efficiency benefits…

… but not all services benefit equally

Page 7: Service-aware Networks over Shared Wireless Access Infrastructure

locations of RAN: private, joint

operators

demand clusters (localized)

traffic demand, by type

each operator wishes to service a fraction of traffic thru private infrastructure

regulatory limitations

build (or update, or disable) private infrastructure

deploy shared infrastructure

Page 8: Service-aware Networks over Shared Wireless Access Infrastructure

Optimization problem!

minimize cost

number of private BSs deployed

proportion of shared BSs used to serve the operator’s traffic

subject to…

all the guaranteed bit rate traffic must be served

a fixed proportion of the operator’s traffic must be served by its private deployment

Page 9: Service-aware Networks over Shared Wireless Access Infrastructure

Algorithms!

We propose two algorithms

selection of where to deploy private infrastructure

selection of where to deploy joint infrastructure

Properties!

Both problems belong to the class of submodular set covering problems (NP-hard)

Both algorithms scale linearly with the scenario they operate on

Results!

Inaproximability: under any traffic demand, this is the best an operator can do unless it solves an NP-hard problem

Approximation ratio: can derive a bound on how far from the optimum is achieved by the algorithm

Page 10: Service-aware Networks over Shared Wireless Access Infrastructure

Data Set!

Call detail records from two operators in Ireland

For each transmitter: position, azimuth, sectorization, coverage area.

For voice call and data session: transmitter where it started/ended, duration, amount of data

Page 11: Service-aware Networks over Shared Wireless Access Infrastructure

Traffic Projection!

Cisco Virtual Network Index

Traffic projected to grow at 61% annual rate between now and 2018

Video (GBR) will account for 69% of the traffic

Identify 33,000 demand points

No point corresponds to an area larger than 6.5 sq km

No point corresponds to a population of more than 500 subscribers

Number of points can be adjusted for higher/lower granularity planning

Page 12: Service-aware Networks over Shared Wireless Access Infrastructure

θ = 0.5

Page 13: Service-aware Networks over Shared Wireless Access Infrastructure

geographic distribution of cost: θ = 0.1 (left) and θ = 0.9 (right)

Page 14: Service-aware Networks over Shared Wireless Access Infrastructure

geographic distribution of rate: θ = 0.1 (left) and θ = 0.9 (right)

Page 15: Service-aware Networks over Shared Wireless Access Infrastructure

Take-away!

By increasing θ, operators must deploy more infrastructure to serve the same amount of GBR traffic

Private BSs experience higher load

For θ = 0.5, half the traffic is served by private BSs, although these account for 25% of all infrastructure used by the operator

The vast majority of private BS deployment occurs in urban areas

Higher θ corresponds to higher costs, and more idle capacity

Most of the effects of sharing are felt by high data rate best effort traffic, especially in urban areas

Page 16: Service-aware Networks over Shared Wireless Access Infrastructure

Planned!

Clean-slate: network planning that accounts for shared infrastructure

Evolution: effects of sharing on upgrading and decommissioning of cellular infrastructure

Regulatory constraints: Herfindahl index

Unplanned!

Crowdsourcing of wireless infrastructure

Dense, largely unplanned deployment by operators

Potential for spectrum sharing, RAN sharing

Page 17: Service-aware Networks over Shared Wireless Access Infrastructure

Sharing and Small Cells!

Open subscriber groups

Small cells as infrastructure contributors to virtualised wireless access (Networks without Borders)

Small cells operating in shared spectrum

Multi-antenna use to realise spectral and energy gains

Indoor Dual stripe

Outdoor Stachus Square, Munich

Page 18: Service-aware Networks over Shared Wireless Access Infrastructure

MU-MIMO and Small Cells!

With MU‐MIMO, multiple UEs are spatially multiplexed on different beams within the same time/frequency resource block

Co-scheduled users must have (semi-)orthogonal precoders

With few subscribers per small cell, difficult to find UEs that can be paired for MU-MIMO

Page 19: Service-aware Networks over Shared Wireless Access Infrastructure

MU-MIMO across Small Cells!

Taking advantage of high cell densification, pair UEs across small cells

Emptied cells can be put into sleep mode

Page 20: Service-aware Networks over Shared Wireless Access Infrastructure

Reassignment!!

A. Selection of considered UEs • UEs must experience sufficiently high SINR • Expected data rate in target cell must exceed rate

in home cell by an offset t !

B. Check for target UEs !C. Selection of UEs to reassign from the set of

reassignable UEs • Maximize the number of deactivated eNBs • Version of set covering problem (NP-hard, but

polynomial-time heuristics exist)

Page 21: Service-aware Networks over Shared Wireless Access Infrastructure

Percentage of eNBs Deactivated

Indoor Outdoor

Page 22: Service-aware Networks over Shared Wireless Access Infrastructure

Power savings

Power consumption modelled according to the EARTH FP7 project

!

!

Power parameters different for micro-, pico-, femto-cells

Page 23: Service-aware Networks over Shared Wireless Access Infrastructure

Increase in Spectral Efficiency

Indoor Outdoor

Page 24: Service-aware Networks over Shared Wireless Access Infrastructure

Take-away!

MU-MIMO-based UE reassignments and centralised control of small cell sleep states can achieve simultaneous increases in spectral efficiency and reductions in energy consumption

It was possible to switch in excess of 25% (indoor) and 35% (outdoor) of small cells to a sleep state whilst still achieving considerable gains in spectral efficiency

Page 25: Service-aware Networks over Shared Wireless Access Infrastructure

Sharing: why stop at spectrum?

Base stations, backhaul, storage, processing, back office…

Virtualisation: why stop at SDNs?

Service-aware virtual wireless networks built on a programmable network substrate and orchestrated in response to a specific service need

Page 26: Service-aware Networks over Shared Wireless Access Infrastructure

Acknowledgements!!

Service-aware planning work by Jacek Kibilda, Francesco Malandrino, and Nick Kaminski

Small cell work by Danny Finn

Work funded by the Science Foundation Ireland

More info: luizdasilva.wordpress.com